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Tag Archives: animal cognition

by The Corvid Blog

I tend to leave incidental posts, responses to Tumblr posts, and Tumblr replies to the Tumblr incarnation of this blog, trying to keep this official Coyot.es space more for original content and longer posts. However, this reply was lengthy enough and contained enough original material beyond the initial reply that I thought it would be good to post it here.

I appreciate you pointing out this distinction, though manufacture versus use is sort of a continuum, depending on how we are defining “manufacture”. It is true that New Caledonian crows are amazing tool makers (something I give lectures about on a nearly annual basis when I talk about animal culture), but more than three species make tools. Chimpanzees, of course, are tool makers, along with documentation of manufacture in orangutans, mandrills, and Asian elephants. This is leaving out animals that develop tools or can be taught to develop tools in captivity (ex. bonobos, hyacinth macaws, and a Goffin’s cockatoo, just to name a few). Also depending on how complex the manufacture, gorillas have been observed breaking off large sticks for stabilization, woodpecker finches have to break off cactus spines to use them (and more recently they are modifying non-native blackberry spines), and bottle-nosed dolphins have to select and break sponges off their substrate to use them. I still assert that we will probably find a lot more tool use and manufacture in the wild, the more chances we get to observe different species in the wild. There are certainly many anecdotal and incidental observations of many more species creating and using tools. However, what you have to keep in mind is that if an animal gets along fine without making and using tools, then there’s not point in them doing so. Tool manufacture and modification, while really cool to us, isn’t always necessary for other animals. In chimpanzees and humans, for example, tool use is integral in how we forage and exist in the world, but for other species tool manufacture and use may only be needed on occasion, when a situation calls for it.

In the case of New Caledonian crows, they, like woodpecker finches, live in places that lack woodpeckers. This is significant because it leaves open the niche that specializes in locating, removing, and eating wood boring insects. Rather than spending the time to evolve physical adaptations to do this (like woodpeckers have) these two species use tools to the same ends. Arguably, there is a distinction between woodpecker finches (which are actually most likely in the tanager family, despite the common name) and New Caledonian crows when it comes to the cognitive department.

What happens when nature takes a bird, already a part of a large-brained, cognitively complex genus of birds (Corvus) and puts it on an island that has a goldmine of a niche to fill? You get the incredible New Caledonian crow (Corvus moneduloides).

So if the birds could manufacture and use tools completely on their own, what makes them more noteworthy than woodpecker finches or other animals that innately use tools? What makes them rival and often exceed chimps in the cognitive department? Tradition, the understanding of the functional properties of their tools, innovative use of tools, and cumulative tool evolution all combine to make NC crows stars in the world of animal cognition.

Gray and Hunt found that different tool types were being used by NC crows in different regions of New Caledonia. These tool types were not reproduced by Kacelnik’s captive crows, which lends more support to those tools’ forms being based on a tradition, or culture, rather than just a genetic ability to make them (after all, humans babble as a precursor to language). NC crows also understand the functional properties of the tools they use and make. They use a range of materials and techniques for making tools, demonstrating that it’s the crow that decides on the tool, not the material. Understanding of the functional properties of their tool was also demonstrated by Betty bending the wire, and again in further experiments. One experiment even showed that the crows could determine the rigidity of tools that would be appropriate for a task. Finally, NC crows show cumulative tool evolution, something we humans still clung to as unique to us. Cumulative tool evolution is the ability to take a tool and modify it to a different or better function and build on previous technology. The tools that were created by precisely snipping and tearing Pandanus spp. tree leaves (the form of which were not replicated by Kacelnik’s captive birds) showed strong evidence of enhancement over time. Hunt and Gray found and compared tool types and their functions from all over the island, including historical records of negatives left in leaves up to four years old. Their findings suggest that the Pandanus tools have had significant improvement on their shape and function. If this doesn’t blow your mind, I don’t know what will!!

I’m a huge fan of NC crows, if it wasn’t apparent. One of my most treasured possessions is a genuine Pandanus tool made by a New Caledonian crow. I even had one of Hunt and Gray’s papers signed (how big of a nerd can I be?), but that was sadly destroyed in a flood. It is a life goal to make it to New Caledonia and observe these birds in the wild. Thank you Pamela Turner for giving me an excuse to blather about NC crows and I hope all of you who read this now appreciate them as much as I do!